Lubricants and lubricant additives



Patented Sept. 4, 1951 LUBRICANTS AND LUBRICANT ADDITIVES John D. Bartleson, East Cleveland, and Herman P. Lankelma, Shaker Heights, Ohio, assignors to The Standard Oil Company, Cleveland,,0hio, a corporation of,0hio i 'No Drawing. Application June 7, Serial No. 753,363

. 2 Claims. (01. 25244gwi This invention relates to lubricants and lubricant additives comprising a reaction product of a mercaptan with a preformed reaction product of an olefin with a phosphorus sulfide.

Lubricants made in accordance with the invention are relatively non-corrosive. and nonlacquer forming. They are suitable for use under various conditions, including high temperatures or high pressures or both, as, for instance, use in an internal combustion engine operating at high temperatures and in which the lubricant is in close contact with metallicsurfaces, metal compounds and high temperature gases.

The art appreciates that many diverse factors are involved in attaining a single lubricating oil addition agent which imparts to the oil little or no lacquer formation and also shows little or -n0 I deterioration or corrosion of metals, especially bearing metals with which the lubricant comes in contact, as well as low oxidative deterioration, as indicated by low viscosity increase,sludge formation, etc. It is very difficult to produce a single addition agent which is nearly optimum for all these factors, especially at a commercially interesting cost.

The art is confronted with the problem of producing a low cost additive for lubricating oils and greases, and one approach to this problem is to.

prepare the desired composition from low cost raw material.

In accordance with the invention, it has been found that the reaction product of an olefin with a phosphorus sulfide may be further reacted with a mercaptan, and the resulting reaction product is an excellent lubricant or additive for lubricants. These reaction products have good solubility in oils and greases, and improve the corro sion, lacquer, sludge, viscosity increase, and the like characteristics thereof.

The objects achieved in accordance with the be subsequently removed. A heavy oil such as whiteloil, or a lubricating oil having about the same properties as that to which the new composition is to be added may be used as a diluent. Thereaction is usually complete in about 10 hours or less time. The reaction time is not critical and is a function of the temperature, the amount of the sulfide that is to react, the subdivision of the reactants, the rate of stirring, etc., as will be understood in the art.

The olefin or mixture of olefin may be reacted with the phosphorus sulfide or a mixture of phosphorus=sulfide in mol ratios from 1 to 3 mols of mono-olefin per mol of the phosphorus sulfide, preferably 2 mols of mono-olefin. per mol of phosphorus sulfide; if a (ii-olefin is used, the amount of di-olefin would be half of the above; if a tri-olefin, one third the above, and so on. An excess of either reactant may be used if desired, e. g.,f or commercial reasons.

Phosphorus pentasulfide is preferred, although other phosphorus sulfides or mixtures of sulfide may be employed. Phosphorus pentasulfide is mosteconomic and readily available and for this reason is used in the illustrative examples. Under "suitable conditions sulfides of arsenic or antimony may be similarly employed.

product may be made with direct admixture of the reactants, or, if desired, by their admixture in the presence of a diluent which may or may n9t In general, olefins'having atleast about 4 to 6 carbon atoms in the molecule are suitable. As an upper limit, the high molecular weight olefin polymers arealso suitable. These olefin polymers may'be'prepared by the polymerization of low molecular weight olefins, as is known to the'art. Their molecular weight generally ranges above about -60,-preferab1y about 125 to 300, and such polymers are known which have a molecular weight the range of about 3,000 to about 50,000. f

The advantages of the invention are particularly apparent in the case of products obtained from olefins having from about 6 to about 25 carbon atoms in the molecule. A commercially desirable olefin is so-called motor polymer or reduced motor polymer. Motor polymer is usually made from C3 and C4 olefins by non-selective polymerization, e. g., with a phosphorus acid type catalyst. Motor polymer boils in the range of to 500 F. with a major portion in the range of to 400 F. A polymer gasoline fraction may be removed therefrom by fractional distillation to the 250 F. cut point, or there-- abouts, and this reduced form of motor polymer is particularly useful. Its average molecular weight is about and it preferably contains a majorian ount of highly branched oleflns boiling U below 600 F. The olefins used should be of a sufiiciently high or suitable molecular weight to give a final product having the desired oil dispersibility.

The reaction may be carried out in the presence or absence of air or in theatmosphereof ine1fl :";'i or non-deleterious gas, such as nitrogen or Hrs; It may also be carried out under pressure, e. g., the pressure generated when the reaction is carried out in a closed vessel.

A reaction temperature in the range of 200 to 500 F. is suitable, although a higher temper ture which is below that at which the reaction product would be decomposed-could 'b'e -'use A temperature in the range of 300 to 400 F. is preferred.

If desired the primary reaction product mayihe. filtered but generally a sludge is not formed w If one is formed it may be removed by centrifug--- ing or filtration, or may remain and be removed afterthenext step.

The primary phosphorus sulfide-olefin reaction: product 15' then treated with-one or moreinen captains--01 mixtures thereof, 1; e., aliplaatic, aromatic; cycloaliphatic and heterocyclic com pounds containing at least one mercapto-or thiol; group; and preferably one to twelvecarbon-atoms per molecule. Hydrocarbon -mercaptans are preferred, such as aliphatic; 'a-licyclic; a-rom-atic-,-- aryl-alkyl, etc., mercaptans.--These-mercaptans may beillustrated by the following: 'methanthiol, ethanthiol; isopropanthiol normal propanthiolp a buta-nthiol, a pentanthiol,';an isopentanthiol; a cycloh'exanthiol; benzyl mercaptan, phenyl ethyr W mercaptan, thiophenoh a methyl;thiophenol;'-a

polyalkyl thiophenol; ethyl thiophenol,-;diethy1--r thiophenol, alkoxy thiophenols; methoxythiophenol, polytl iol v mercaptans; thioresorcinol, and (ring) alkyl substitutedthioresorcinol; and thelike mercaptans. 'The wordfmercaptan is used in its generic sense to includeanyof the-above-- 'types of compounds, andcorresponding-"com--- i cu ed lie ere. se ondary, rea on. 1

may be started under reflux conditions, the ,re-i x...temp. r .ture rising. as the,,reaetion nrqeeeg andsu ie te to pressurein or e ie carry. th ir, reaction to final completion. to

The-amount of the ,mercaplian, ,used .not criticaL, 1 Even small amounts Sh w .p improyement. An excess of a volatilclnercaptap ybe r mo afte rfe mation o th se end mi reactipn product. A suitable amount oj mer co cant n -is hat ..s i hiometr e ly.ilequivale to. g N the; saponification number of the. primary 2 readtion; product, although an excess. which 1 3-; ye or which remains. ee i all .fli tliallmz-;;. ful. V 7O Ihareaction; lnass is A then preferably centri} fu e r filter d to r ove a y b eduets udse formed. Any excess of a volatile reactant, or a v latile diluentbmay be remained y va uumin -1r.

be solvent extracted with a suitable solvent, e. i. liquid propane or isopropyl alcohol.

The amount of the final reaction product (i. e., the additive) to be incorporated in an oil or grease will depend upon the characteristics of the oil 101 reaseEand-the intended use; Some oils haveimorerof a; tendency to. corrode metals, or to form acids, sludges and lacquer deposits than others, and such oils require larger quantities of the additionmagentrWAlso, oils that are intended for higher temperatures require larger amounts of totthe. reactionme r 4. Reach. .n-nrodii in rktq; qsarts eineh xan thioLwith:0ne-=.Q3 1l1:. h re ct ens qductr mol of P2S5 with 1 to 3 mols of motqr pclymer e11 eacted at iii-temperature in. th zranee; Q 12 5. Reaction. p oduct of 11120110. pa se methexr. phenylz mercaptan witheona-partzof the ;:reacti9 product of 1 mol of P285 with 1 to 3.-\mols.;.of dodecenel, all reacted: at a:' temperature in: the 5 range of 2508 to 500 21; V V

6. Reaction -productiof 1-to:l0 partsof pr-'(n-";

amylithio phenol with cne-part of the. reactions .product of -1= motor-P285 with l to 3 mols-of n' octyl-cycloliexene all reacted ata temperature in the'rang eof 250 40 500 1 iii 7. Reaction-productof l to l0 parts-of lauryl r mercaptan with one part-of the reaction product of Hnfol'of Pzss with 0$5-to 1.5 mols'of deca-d-iene-e V 2,8,'-{ a ll reacted at atemperaturein the' range o1 fi 0 50 ;F-

8. Reactionproductof l to lOparts of resorcin-:... thiol-with" one part ofthe reactionproduct-hot mol of P}:v with=lto 3 mols of hepta-decene-fi; all reacted; at a temperature-in the 'range of 250 to 5003?: V 7

9. Reaction product of l'to IOpartsof benzyl mercaptan with one part of the; reaction product of 1 'molof P255 with l to 3 molspf motorpoly- 5 mer, all reactedat atemperature in therange oil 2505110 500" 7 10. Reaction productoi l to -10"par ts-of nh pianthici with one part ofthe reaction- -prod-- tillation"; If desired, the resulting" product may =75. uct'of' l irkol of Pzss'with l'to 3mo1s of n-octene-Z} rall reacted at a temperature in the range of 200 to 500 F The following specific embodiments and tests runner illustrate the invention:

38 parts of P2S5 are mixed with 62 parts of re-i duced motor polymer and agitated for 8 hours at 850 a pressure reaction vessel, at a pressure of about 100 pounds per square inch. Some gas is vented during the reaction, depending upon the free space in the vessel, in order to maintain this pressure. No sludge is formed but it is preferred to filter the primary phosphorus sulride-olefin reaction product; Volatile material can be distilled off if desired. i

EXAMPLE I 200 grams of the above sulfide-olefin reaction product is mixed with 125 grams of n-dodecyl mercaptan and agitated for 8 hours at 350 F. in a closed ,reaction vesseLat a pressure of 100 pounds per square inch. Depending upon the free space in the vessel, some vapor is vented during the course of the reaction, in order to maintain this pressure. The reaction product is filtered hot. A 88.4% yield of reaction product is obtained, and 2.8% sludge. The molecular weight was 379 (determined by the cryoscopic method). This product is referred to as additive I hereinafter.

EXAMPLE II 400 grams of the above sulfide-olefin reaction product. is mixed with 94 grams of isopropyl mercaptan and agitated for 8 hours at 350 F. in a closed reaction vessel, at a pressure of 100 pounds'per square inch. Depending upon the free space in the vessel, some vapor is vented during the course of the reaction, in order to maintain this pressure. The reaction product is filtered hot. A 92.5% yield of reaction prodnot is obtained and no sludge. This product is referred to as additive II hereinafter.

EXAMPLE III 400 grams of the above sulfide-olefin reaction product is mixed with 129 grams of commercial amyl mercaptan and agitated for 8 hours at 350 F. in a closed reaction vessel, at a pressure of 100 pounds per square inch. Depending upon the free space in the vessel, some vapor is vented during the course of the reaction, in order to maintain this pressure. The reaction product is filtered hot. A 91.9% yield of reaction product is obtained, and only 0.94% sludge. The product analyzed 9.07% P and 23.30% S. This product is referred to as additive III hereinafter.

In testing oils containing the addition agents the so-called standardized Chevrolet Engine Test is used. In this test, new piston rings and two new copper-lead bearing inserts are installed in the motor prior to each test. The engine is a conventional Chevrolet engine with 216.5 cu. in. piston displacement and a compression ratio of 6.5 to 1. The engine is operated at 3150 R. P. M. with a load of 30' B. H. P. and at a temperature at the jacket outlet of 200 F. The lubricating oil temperature is maintained at 265 F. for an SAE 10 grade oil, and at 280 F. for oils of SAE 30 to 50 grades. The fuel used contains from 2.5 to 3.0 ml. tetra-ethyl lead per gallon. Besides the weight loss of the test bearings, deposits in the power section, and properties of the used oil, sampled near the middle and also at the end of the test, are examined.

A conventional solvent extracted lubricating 011 base Stock ($AE 30) and blended compositions of this-0'11 madein accordance with the 'iii vention were submitted to36-hour tests in ac cordance with the above Chevrolet engine pro= cedure. The results in the following table are typical.

TABLE A Additive of Example No None Concentration of Additive, in Per Cent by Weight... I 0 1 1.0 Overall Rating 92.00 00150 Corrosion of Cu-Pb Bearing Metal (in mgms weight.

loss per bearing half-shell) 1,428 21' AcidNumberhnQ i 2.4 "0.77

l 0.1% lecithin which gives a clearer oil and does not afiect the other properties. i

Table A illustrates the great improvement in the corrosion characteristics of a solvent ex-: tracted oilwhen only 1.0% of a reaction product, in accordance with the invention, is incorporated therein. The solvent extracted oils are generally suitable in all characteristics except corrosion, and it will be seen that the oil containing the additive of the invention is also suitable as to all other characteristics in addition to being very markedly improved (nearly about seventy-fold) as to the corrosion characteristic.

Lubricating oils containing representative additives, prepared in accordance with the invention, were also laboratory tested by the Sohio test procedure described in U. S. Patent No. 2,403,474 except that the amount of iron salt is increased to 0.05% under the Iron Tolerance" conditions. i

Iron Tolerance tests were made on a conventional medium duty acid-treated Mid-Com tinent lubricating oil base stock (SAE 30) and compositions of this oil with additives, prepared in accordance with the invention. The results given in the following table are representative.

TABLE B Additive of Example No n None I II III Concentration of Additive, in Per Cent by Weight 0 3 3 3 Corrosion (in milligrams weight loss) of Cu-Pb i. 0.2 l.4 1.3 0.2 Viscosity Increase (SUS) l, 540 46 48 71 Sludge (Pentane Insolubles), in

Weight Per Cent 6. 87 0.68 0. 0. 50 Acid Number 7. 8 l. 4 l. 6 1. 0 Lacquer Deposit (milligrams) 12.1 0.9 0. 0 0. 0

I aspects, including variations and modifications thereof.

In some instances, it is desirable to include in a lubricating oil containing the additive an agent for improving the clarity of the oil, e. g., lecithin, lauryl alcohol, and the like, which agents are known to the art. In order to prevent foaming of the oil containing a small proportion of the additive, it is desirable in some cases to add a very small amount of tetra-amyl silicate, alkyl ortho carbonate, ortho formats, or ortho acetate,

era polyalkylsilicone oil for preventingfoaming upon bubbling of air through oil containing a few percent of the additive.

'It is intended to claim-the invention broadly,

except as limited by the following claims;

We claim: 7 r V V 1. An oil-dispersible product of the reaction at 350 F. for eight hours of 1.15 moles ethyl mercaptan to each mole of a reaction product of 1 mole of phosphorus pentasulfide and 1.5

gether at350 F. for eight hours to produce an oil-dispersible material-suitable for improving the characteristics of a mineral lubricating oil.

2 .5 lubricant comprising a mineral lubricating oil and an amount sufficient to inhibit the oxidative; deteriorationin use of the oil of an oil-dispersible product of the reaction at 350 F. for eight hours of, 1.15 moles ethyl mercaptan to each mole of a reaction product of 1 mole of V. 10 moles of reduced motor polymer reacted to- V phosphorus pentasulfide .'and-1.5 vmoles ;of:re=; duced motor polymer reacted togetheratififi", F. for eight hours to'produce an 'oil-dispersihle material suitable for improving .the' characteristics of aminerallubricating 011.. i "JOHN D. BARTLESON.

HERMAN P. LANKELMA.-

REFERENCES CITED 7 The following references are of record in the file of 'thispatent: I a Q UNITED STATES Pn'i'nn'rs I 1 F we 

2. A LUBRICANT COMPRISING A MINERAL LUBRICATING OIL AND AN AMOUNT SUFFICIENT TO INHIBIT THE OXIDATIVE DETERIORATION IN USE OF THE OIL OF AN OIL-DISPERSIBLE PRODUCT OF THE REACTION AT 350* F. FOR EIGHT HOURS OF 1.15 MOLES ETHYL MERCAPTAN TO EACH MOLE OF A REACTION PRODUCT OF 1 MOLE OF PHOSPHORUS PENTASULFIDE AND 1.5 MOLES OF "REDUCED MOTOR POLYMER" REACTED TOGETHER AT 350* F. FOR EIGHT HOURS TO PRODUCE AN OIL-DISPERSIBLE MATERIAL SUITABLE FOR IMPROVING THE CHARACTERISTICS OF A MINERAL LUBRICATING OIL. 